Problem: $2qr + 3r - 4s - 4 = -9r - s + 2$ Solve for $q$.
Explanation: Combine constant terms on the right. $2qr + 3r - 4s - {4} = -9r - s + {2}$ $2qr + 3r - 4s = -9r - s + {6}$ Combine $s$ terms on the right. $2qr + 3r - {4s} = -9r - {s} + 6$ $2qr + 3r = -9r + {3s} + 6$ Combine $r$ terms on the right. $2qr + {3r} = -{9r} + 3s + 6$ $2qr = -{12r} + 3s + 6$ Isolate $q$ ${2}q{r} = -12r + 3s + 6$ $q = \dfrac{ -12r + 3s + 6 }{ {2r} }$